Floating polluted water

So while I was messing around with debug mode, I found a tile of polluted water that was floating in the air. I don't know what causes it to do this, but I reloaded to the start of the world and waited for the piece of polluted ice that had melted into that polluted water to melt again and once again the polluted water was floating.
(Digging tiles around it makes it fall down)

Here is my save file.
Planet.sav
You need to go to the area marked in the image below and wait for the piece of polluted ice with a wheezewort on top to melt. Once it does, the polluted water it melted into should be floating.